Research Of Dynamic Data Integrity Based On CPDP In Multicloud Storage Environment

Multicloud is a new direction of cloud computing in the future. It can provide and help users manage the internal and external resources of the cloud. In addition, multicloud can also balance the load. What’s more, when transaction is failed, multicloud can automatically redeploy the transaction logic. According to the above advantages, some users choose a multicloud to store their data. However, some multicloud storage service providers hide the loss or error information of user’s data for their own interests. Furthermore, in order to save the cloud storage resources, some multicloud storage service providers delete data which is rarely accessed by the user. In a word, many users are hesitant to use multicloud storage services because of data integrity issues. Therefore, how to detect the integrity of user’s data in the multicloud storage environment has become one of the hot topics in the field of information security.Aim at this topic, many researchers proposed various schemes about data integrity verification. In these schemes, some schemes support data integrity verification in the single cloud environment but are not applied to the multicloud environment. Some schemes support data integrity verification in the multicloud, but there are security vulnerabilities and not supporting dynamic operation. Although some schemes support data integrity verification based on PC, do not support data integrity verification based on mobile terminal which has the limited computation and storage resource. Based on the shortcomings and deficiencies of the existing schemes, this thesis researches the verification technology of data integrity in the multicloud from the person computer side and mobile terminal.To solve the problem of low security and not supporting dynamic data update operations in Zhu’s CPDP(cooperative provable data possession, CPDP) scheme in the multicloud environment based on PC, a dynamic data integrity verification scheme in the multicloud based PC is proposed in this thesis. The scheme firstly corrects a flaw in collaborative provable data possession scheme and resists forgery attack from the cloud storage service providers. In addition, in order to achieve transparency verification for the trusted third party and the organizers, an additional data block is added to the scheme. Lastly, this thesis introduces and improves the index-hash table, so that the scheme can support the dynamic update operations. Compared with existing CPDP scheme, this scheme not only improves security of data integrity verification, but also introduces low computation and communication overheads. What’s more, the scheme supports the dynamic update operations.In the multicloud environment based on mobile terminal, owning to the limitations of computing and storage capacity in the mobile terminal, when user uses the scheme based on PC to verify the data integrity, it will increase computing burden of mobile terminal. To solve this problem, a data integrity verification scheme in the multicloud environment based on mobile terminal is proposed. In this scheme, BLS short signature and Merkle hash tree principle are introduced to realize the verification of data integrity. In the scheme, outsourcing verification is supported to Lighten the burden of the mobile terminal, data integrity can be verified without using directly source file block, process of verification can be stateless. It is suitable for mobile terminal.